Courtesy of Petrol Blog An Appreciation of the short lived Citroen GS Birotor
In total, only 847 production vehicles and 47 prototypes were built, estimated that there are only 250-300 worldwide.
The rotary engined GS, known as the Birotor, was launched in September 1973 at the Frankfurt Motor Show. Its specification was undeniably impressive: hydropneumatic suspension, all-round disc brakes, semi-automatic transmission and, of course, a water-cooled, twin rotor engine. The power output of 107bhp was more than respectable, but the engine had the typical rotary weaknesses of high emissions and a lack of low-end torque.
Although marketed as a GS, the new model shared relatively few components with other models in the GS range. Apart from the engine, the hubs, floor pan, suspension, brakes, wheels, instrument panel, interior trim and many of the exterior panels also differed from those utilised in the core GS range.
The price also set the Birotor apart, it being about 70% more expensive than any other GS.
There was one other important difference between the Birotor and its siblings: fuel economy. The Birotor drank fuel at an alarming rate for a car of its size, especially in heavy traffic.
It may have been thirsty, but the Birotor was otherwise a generally well-sorted car. It had excellent road manners, sharing the same supple ride as the rest of the GS range but offering better handling with less understeer and reduced body roll. The gear ratios were suboptimal, however, and the Birotor lacked a little of the promised refinement.
It may not have been perfect, but the Birotor was more than good enough to merit an enduring place in the Citroën range. Fate, though, had other plans for it.
In October 1973, war broke out in the Middle East. I’ll leave the politics of that conflict for others to discuss, but one consequence of it is germane to this tale: the Saudi Arabian-led embargo on oil sales to the USA and the resulting energy crisis.
Although much of Europe suffered little interruption to fuel supplies, the price of crude oil rose sharply. This had an obvious knock-on effect on petrol prices. It was precisely the wrong time to bring a thirsty car to market. In a blink, the Birotor went from niche model to white elephant.
The writing was on the wall for the Birotor, and production ceased in 1975. As manufacturing and stocking spare parts for such a small number of vehicles was not financially prudent, Citroën attempted to buy back every Birotor which had found a purchaser. The terms of the buy-back offer were generous and many owners gladly accepted them.
One might have thought that Citroën would have retained at least some Birotors as donor cars to support those which remained at large. They did not do so. Instead, the company destroyed every Birotor that it had re-purchased as well as all of its unsold inventory. No spares were kept.
The brave, hardy souls that hung on to their Birotors in 1975 were on their own.
Fast forward 40 years. In spite of everything, a number of Birotors (and M35s, for that matter) still exist.
But you’ll struggle to find one. Indeed, the Birotor barely registers in the consciousness of most classic car lovers. And that’s a shame, for in many ways it is the quintessential Citroën. Flawed, yes, but bold, imaginative and stylish.

Very Rare Rotary Engined Citroen GS Birotor only built between 1973 and 1975, in extremely good overall condition. An extremely rare example of Citroen's venture into a Rotary Valve engine based on the NSU design, which was in production for a very short period before being bought back by Citroen and destroyed, with very few remaining. Believed to have been originally owned by a Citroen employee at their R&D division

Four door saloon in very good original condition, with only small blemish in the paintwork

Very good original interior and instruments. Interior is finished in brown tweed.